Buggy code:
public final class TestUtil { private TestUtil ( ) { } public static void assertArrayEquals ( String msg , Object [ ] expected , Object [ ] found ) { } public static void assertSetEquals ( Collection expected , Collection found ) { } public static void assertSetEquals ( String msg , Object [ ] expected , Object [ ] found ) { } public static void assertSetEquals ( String msg , Collection expected , Collection found ) { } public static void assertCommutativeEquals ( Object a , Object b , boolean should ) { } private static void assertHashEquals ( Object s , Object t , boolean should ) { } public static void runMain ( String classPath , String className ) { } public static Object runMethod ( String classPath , String className , String methodName , Object [ ] args ) { } public static void assertMultiLineStringEquals ( String message , String s1 , String s2 ) { } private static void showContext ( List lines ) { } private static String readNonBlankLine ( BufferedReader r ) throws IOException { } public static boolean sameDirectoryContents ( final IMessageHandler handler , final File expectedBaseDir , final File actualBaseDir , final boolean fastFail ) { } static boolean sameFiles ( IMessageHandler handler , File expectedFile , File actualFile ) { } static boolean sameFiles ( IMessageHandler handler , File expectedBaseDir , File actualBaseDir , String path ) { } private static boolean doSameFile ( IMessageHandler handler , File expectedBaseDir , File actualBaseDir , File expectedFile , File actualFile ) { } public static interface ILineator { public static final TestUtil . ILineator TEXT = new TestUtil . TextLineator ( ) ; public static final TestUtil . ILineator CLASS = new TestUtil . ClassLineator ( ) ; TestUtil . CanonicalLine [ ] getLines ( IMessageHandler handler , File file , File basedir ) throws IOException ; } public static class CanonicalLine { public static final TestUtil . CanonicalLine [ ] NO_LINES = new TestUtil . CanonicalLine [ 0 ] ; public final String canonical ; public final String line ; public CanonicalLine ( String canonical , String line ) { } public String toString ( ) { } } private abstract static class Lineator implements TestUtil . ILineator { public TestUtil . CanonicalLine [ ] getLines ( IMessageHandler handler , File file , File basedir ) throws IOException { if ( ( ! ( file . canRead ( ) ) ) || ( ! ( file . isFile ( ) ) ) ) { MessageUtil . error ( handler , ( ( ( "not<seq2seq4repair_space>readable<seq2seq4repair_space>file:<seq2seq4repair_space>" + basedir ) + "<seq2seq4repair_space>-<seq2seq4repair_space>" ) + file ) ) ; return null ; } InputStream in = null ; <START_BUG> String path = FileUtil . normalizedPath ( file , basedir ) ; <END_BUG> TestUtil . LineStream capture = new TestUtil . LineStream ( ) ; try { lineate ( capture , handler , basedir , file ) ; } catch ( IOException e ) { MessageUtil . fail ( handler , ( "NormalizedCompareFiles<seq2seq4repair_space>IOException<seq2seq4repair_space>reading<seq2seq4repair_space>" + file ) , e ) ; return null ; } finally { if ( null != in ) { try { in . close ( ) ; } catch ( IOException e ) { } } capture . flush ( ) ; capture . close ( ) ; } String missed = capture . getMissed ( ) ; if ( ! ( LangUtil . isEmpty ( missed ) ) ) { MessageUtil . warn ( handler , ( "NormalizedCompareFiles<seq2seq4repair_space>missed<seq2seq4repair_space>input:<seq2seq4repair_space>" + missed ) ) ; return null ; } else { String [ ] lines = capture . getLines ( ) ; TestUtil . CanonicalLine [ ] result = new TestUtil . CanonicalLine [ lines . length ] ; for ( int i = 0 ; i < ( lines . length ) ; i ++ ) { result [ i ] = new TestUtil . CanonicalLine ( lines [ i ] , lines [ i ] ) ; } return result ; } } protected abstract void lineate ( PrintStream sink , IMessageHandler handler , File basedir , File file ) throws IOException { } } private static class TextLineator extends TestUtil . Lineator { protected void lineate ( PrintStream sink , IMessageHandler handler , File basedir , File file ) throws IOException { } } public static class ClassLineator extends TestUtil . Lineator { protected void lineate ( PrintStream sink , IMessageHandler handler , File basedir , File file ) throws IOException { } public static boolean haveDisassembler ( ) { } private static void disassemble ( IMessageHandler handler , File basedir , String name , PrintStream out ) throws IOException { } } public static class LineStream extends PrintStream { StringBuffer sb = new StringBuffer ( ) ; ByteArrayOutputStream missed ; ArrayList sink ; public LineStream ( ) { } public String getMissed ( ) { } public void clear ( ) { } public String [ ] getLines ( ) { } public void println ( Object x ) { } public void print ( Object obj ) { } public void println ( char c ) { } public void println ( char [ ] c ) { } public void print ( char c ) { } public void print ( char [ ] c ) { } public void println ( String s ) { } public void print ( String s ) { } public void println ( ) { } } }

Fix:
FileUtil . normalizedPath ( file , basedir ) ;